A. No discharger shall increase the use of potable or process water in any way, nor mix separate waste streams for the purpose of diluting a discharge as a partial or complete substitute for adequate treatment to achieve compliance with the standards set forth in this chapter.
B. This section shall apply to industrial wastes as previously defined and further to any business or industry connected to the city sanitary sewer system who uses more than one hundred thousand (100,000) cubic feet of water in any one month during the calendar year, or who discharges more than one hundred thousand (100,000) cubic feet of waste into the public sewer in any one month during the calendar year, or if the waste contains an average BOD in excess of two hundred forty milligrams per liter (240 mg/l) or a suspended solids concentration greater than three hundred milligrams per liter (300 mg/l) based upon a composite sample. The composite sample shall mean not less than twelve (12) individual samples taken at not less than thirty (30) minute intervals for a period of not less than six (6) hours.
C. Review and acceptance of the city shall be obtained prior to the discharge into the public sewers of any waste having a BOD greater than two hundred forty milligrams per liter (240 mg/l) or a suspended solids content greater than three hundred milligrams per liter (300 mg/l).
D. Where required, in the opinion of the supervisor, to modify or eliminate wastes that are harmful to the structures, processes or operation of the sewage treatment works, the person shall provide at his or her expense such preliminary treatment or processing facilities as may be determined necessary to render his or her waste acceptable for admission to the public sewers.
E. All industries shall provide pretreatment to include, but not be limited to, vibrating or rotary screens to remove any particle larger the twenty (20) mesh.
F. Each person discharging industrial wastes into a public sewer shall construct and maintain one or more control manholes or access points to facilitate observation, measurement and sampling of wastes. Control manholes or access facilities shall be located and built in a manner acceptable to the supervisor.
G. The volume of flow used for computing industrial waste charges shall be the metered water consumption of the person as shown in the records of meter readings maintained by the city. If the person discharging industrial wastes into the public sewers procures any part, or all, of his or her water from sources other than the city water department, all or a part of which is discharged into the public sewers, the person shall install and maintain at his or her expense water meters of a type approved by the supervisor for the purpose of determining the volume of water obtained from these other sources.
H. Industrial wastes discharged into the public sewers shall be subject to periodic inspection and a determination of character and concentration of said wastes. The determinations shall be made as often as may be deemed necessary by the supervisor. The samples shall be collected in such a manner as to be representative of the composition of the wastes. The sampling may be accomplished either manually or by the use of mechanical equipment acceptable to the supervisor. Access to the sampling locations shall be granted to the supervisor or his or her duly authorized representatives at all times. All tests will be run by the supervisor or his or her duly authorized representatives.
I. All persons discharging industrial wastes into the public sewers shall be subjected to a surcharge, in addition to any other sewer service charges, if these wastes have a concentration greater than either of the following maximum concentrations:
1. A BOD of one thousand milligrams per liter (1,000 mg/l);
2. A suspended solids content of one thousand five hundred milligrams per liter (1,500 mg/l);
3. An average BOD loading of seven hundred fifty (750) pounds per day.
The amount of the surcharge shall reflect the cost incurred by the city in removing the excess BOD and suspended solids and cost of additional testing necessary should an industrial user exceed the maximum concentrations.
J. The surcharge per person shall be set by resolution of the city council for each and every calendar day that the average concentration of BOD or suspended solids exceeds the maximum limits outlined. Sampling shall be performed as previously outlined. The surcharge shall be in effect for each and every calendar day after notification that test results on samples show the concentration of BOD or suspended solids exceed the maximum allowable limits.
K. The BOD in pounds per day loading shall be computed by multiplying the person's metered water flow in million gallons per day by the constant eight thousand three hundred forty five (8,345) and multiplying this product by the person's average daily concentration of BOD in milligrams per liter. Devices for measuring the volume of waste discharged may be installed, owned and operated by the person following approval of the supervisor, and these devices may be used for determining volumes of waste discharged in lieu of the metered water volume if approved by the supervisor. (Ord. 624-08, 8-12-2008)